> Four trials were cluster-RCTs, with all participants in the intervention clusters required to wear masks, thus assessing both source control and personal protection
> In two [of the four] trials the clusters were households with a member with new influenza; neither of these studies found any protective effect
> In two [of the four] trials the clusters were college dormitories during the influenza season; neither study found any reduction
I wouldn't go as far as saying that masks do not work. At the same time, I wouldn't go as far as saying that they do work.
Reality is messy. If you want to wear a mask, do it. If not, don't.
I understand that in this era of "alternative facts" the view is not universally shared, but I do believe that reality contains objective truths if only we can get at them.
Either masks hinder the spread of germs (in the prior this has high probability based on logic and the experience of many years) or they don't.
We are down to four trials now instead of nine, and only three that count, since one was excluded by these authors for methodological shortcomings.
Don't blame it on "reality" that none of these was sufficiently large to establish the truth either way.
Let me rephrase: If you feel the need to wear a mask, do it. If not, don't.
Edit:
> in the prior this has high probability based on logic and the experience of many years
Reality can be counter-intuitive if you put your logic and experience to the test. Famous example: Using diuretics for antidiuretic effects [1]
Even a banal situation like wearing a face mask during surgery leads to inconclusive results [2]. Does it increase or decrease the number of cases of wound infections? There seems to be no clear evidence atm
